字符串学习总结

1. //判断字符串是否包含“|”
       string aaa="123";
       if (aaa.Contains("|") == true)
       { Response.Write("you"); }
       else
       { Response.Write("meiyou"); }
2.  //删除重复字符串
        string st = "1,2,3,23,3,24,34,23,3";
        string[] stArr = st.Split(',');
        ArrayList al = new ArrayList();
        foreach (string qq in stArr)
        {
            if (!al.Contains(qq))
                al.Add(qq);
        }
        st = "";
        for (int i = 0; i < al.Count; i++)
        {
            st += al[i] + ",";
        }
        st = st.Substring(0, st.Length - 1);
        Response.Write(st);
3. //剪取字符串
        string[] str = new string[5]
              {"张晓梅的好友/注册时间为/09-08-04 10:40:2/已注册 ",
               "张晓梅的好友/注册时间为/09-08-05 3:30:10/已注册 ",
               "张晓梅的好友/注册时间为/09-08-06 12:32:14/已注册 ",
               "张晓梅的好友/注册时间为/09-08-07 9:58:52/已注册 ",
               "张晓梅的好友/注册时间为/09-08-08 10:40:30/已注册"
              };
        foreach (string a in str)
        {
            string[] cc = a.Split('/');
            Response.Write(cc[2] + "<br/>");
        }
4. //日期变化，设定固定时间
        DateTime now = System.DateTime.Now;
        string aa = now.ToString();
        string dd=aa.Remove(10);
        string bb = aa.Replace(aa,dd+"08:00:00");
        DateTime ee = Convert.ToDateTime(bb);     
        Response.Write(ee);
5.//判断是否存在星期六，星期天
        DateTime aa =Convert.ToDateTime( "2009-09-01");
        DateTime bb =Convert.ToDateTime( "2009-09-07");
        for (DateTime dt = aa; dt <= bb; dt = dt.AddDays(1))
        {
            if (dt.DayOfWeek == DayOfWeek.Saturday || dt.DayOfWeek == DayOfWeek.Sunday)
            { Response.Write("Exist"); }
        }